Fix `Rails/WhereExists` cop in app/lib (#28862)

.rubocop_todo.yml

@@ -77,10 +77,6 @@ Rails/WhereExists:
   Exclude:
     - 'app/controllers/activitypub/inboxes_controller.rb'
     - 'app/controllers/admin/email_domain_blocks_controller.rb'
-    - 'app/lib/activitypub/activity/create.rb'
-    - 'app/lib/delivery_failure_tracker.rb'
-    - 'app/lib/feed_manager.rb'
-    - 'app/lib/suspicious_sign_in_detector.rb'
     - 'app/policies/status_policy.rb'
     - 'app/serializers/rest/announcement_serializer.rb'
     - 'app/workers/move_worker.rb'

app/lib/activitypub/activity/create.rb

@@ -320,7 +320,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     already_voted = true
 
     with_redis_lock("vote:#{replied_to_status.poll_id}:#{@account.id}") do
-      already_voted = poll.votes.where(account: @account).exists?
+      already_voted = poll.votes.exists?(account: @account)
       poll.votes.create!(account: @account, choice: poll.options.index(@object['name']), uri: object_uri)
     end
 
@@ -406,7 +406,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
 
     return false if local_usernames.empty?
 
-    Account.local.where(username: local_usernames).exists?
+    Account.local.exists?(username: local_usernames)
   end
 
   def tombstone_exists?

app/lib/delivery_failure_tracker.rb

@@ -28,7 +28,7 @@ class DeliveryFailureTracker
   end
 
   def available?
-    !UnavailableDomain.where(domain: @host).exists?
+    !UnavailableDomain.exists?(domain: @host)
   end
 
   def exhausted_deliveries_days

app/lib/feed_manager.rb

@@ -421,7 +421,7 @@ class FeedManager
     check_for_blocks.push(status.in_reply_to_account) if status.reply? && !status.in_reply_to_account_id.nil?
 
     should_filter   = blocks_or_mutes?(receiver_id, check_for_blocks, :mentions) # Filter if it's from someone I blocked, in reply to someone I blocked, or mentioning someone I blocked (or muted)
-    should_filter ||= status.account.silenced? && !Follow.where(account_id: receiver_id, target_account_id: status.account_id).exists? # of if the account is silenced and I'm not following them
+    should_filter ||= status.account.silenced? && !Follow.exists?(account_id: receiver_id, target_account_id: status.account_id) # Filter if the account is silenced and I'm not following them
 
     should_filter
   end
@@ -434,7 +434,7 @@ class FeedManager
     if status.reply? && status.in_reply_to_account_id != status.account_id
       should_filter = status.in_reply_to_account_id != list.account_id
       should_filter &&= !list.show_followed?
-      should_filter &&= !(list.show_list? && ListAccount.where(list_id: list.id, account_id: status.in_reply_to_account_id).exists?)
+      should_filter &&= !(list.show_list? && ListAccount.exists?(list_id: list.id, account_id: status.in_reply_to_account_id))
 
       return !!should_filter
     end

app/lib/suspicious_sign_in_detector.rb

@@ -19,7 +19,7 @@ class SuspiciousSignInDetector
   end
 
   def previously_seen_ip?(request)
-    @user.ips.where('ip <<= ?', masked_ip(request)).exists?
+    @user.ips.exists?(['ip <<= ?', masked_ip(request)])
   end
 
   def freshly_signed_up?